The present invention relates to a substrate method of repairing a array, and more particularly to a method of repairing a substrate array for a BGA (ball grid array).
FIG. 1 shows a substrate array for a BGA. This structure of substrate array 10 is comprised of a frame 12;14 and a plurality of substrates 16 mounted in the frame 12;14. The frame 12;14 has connecting portions 18 respectively connected to the substrates 16. When chips are installed in the substrates 16 and the whole assembly are packaged, the connecting portions 18 are cut off, and therefore individual chip and substrate packages are provided and respectively separated from the frame 12;14.
However, the yield of the manufacturing of substrate arrays 10 is not 100%. It is quite normal that the yield is about within 70% to 80%. Some factories may achieve 90% or higher, and some others may be unable to achieve 70%. The yield depends upon the manufacturer's fabrication technology. In case a defective substrate 16' exists in a substrate array 10, the substrate array 10 becomes useless. A defective substrate array 10 may be thrown away, or sold at a very low price for use in training. Further, low yield results in a short supply of substrate array.